1. Field of the Invention
This invention relates to an improvement within a fuel injection valve for an internal combustion engine, and more particularly, to a fuel injection valve characterized by especially low spray speed and high automization of the fuel spray.
2. Description of the Prior Art
Heretofore, variously outwardly opening type fuel injection valves have been proposed for injecting fuel into the suction pipe or intake manifold of gasoline powered, internal combustion engines. In such fuel injection valves, while the spray speed is relatively high, the spray particles are liable to be relatively large in size and as a result, the injected fuel is apt to adhere to the wall of the suction pipe or manifold, and when the adhered fuel is admitted or sucked into the cylinder by suction air during the suction stroke of the piston with the control of fuel quantity is unfavorably lost which has unfavorable effects on control of exhaust gas pollutants.
Heretofore, volute type injection valves have been proposed as a means for promoting atomization of the spray by use of a continuous air current which impacts the liquid spray and facilitates atomization of the fuel particles. In such valves, however, the gyrating current is effected on the upstream side of the valve seat, and the gyrating energy is lost each time the injection of fuel is interrupted. Particularly where small quantities of fuel are injected such as during engine idling, a gyrating current sufficient to promote atomization is in fact not obtained.